I just bought a 1990 XT600 and it needs fork seals. Has anyone ever done it themselves and how hard is it? Tools required, time, tricks? Any response greatly appreciated. Thanks

It's fairly easy assuming you've got proper tools and know how to do it.

The only (almost) way to get the oil seals out is by disassembling the fork tubes.
Special tools you need are an impact driver for the allen bolt that holds the damper rod at the bottom of the fork tube (or a makeshift tool to prevent the damper rods from turning inside the fork tubes)
A pair of thin nose pliers or circlip pliers is helpful to remove the circlips that secure the seals.

If you have a fork that allows to preload it with air pressure you can get the seals out without disassembling the fork. Just drain the oil, plug up, remove the circlip and pump up the fork tube until the seals pop out.

You can usually use the old seals as a makeshift driver to press the new ones into place.

Fill up to the required level of fork oil. It is much easier ands more accurate to measure the oil level / air chamber than to measure the oil volume.

Always clean the inside of the tubes and the dampers thoroughly before reassembly. Always use new fork oil. Always replace the dust seals together with the oil seals. Check the inner tubes for scratches or stone chips that might have caused the seals to fail. Small chips and scratches can be smothened with an oil stone and polished. Rusted inner tubes are a case for replacement or rechroming.

Invest into a workshop manual if you want to work on the bike.

Thanks for the insight! I just got the bike and it came with the yamaha service manual and it will be put to use. Right now I took all the plastic/seat and airbox off so I can clean it all up. Once I get finished doing that it is onto the chain and the forks. The bike only has 5,000 miles or so and the motor sounds really good. It was left near a wood pile and aquired a good sunburn on the plastic and seat. I'm thinking of painting the plastic but I'll wait and see once the mechanicals are taken care of. Any ideas of a cool paint scheme?

I replaced my fork seals this past July. They were on my old Honda. I found on the internet a way to replace the seals without disassmbling the forks . It involves removing the fork from the bike then fully extending the fork and filling it to the top with more oil then putting the cap back on ( I used ATF).
Now lay the fork horizontal and level supporting 1 end solidly ..against a garage door frame worked for me then using a jack to compress the fork from th eother end.The pressure of the fluid will force the seal out. This is very messy but works although I had 1 seal that came out crooked and had to be pried out gently with a screwdriver.

Try this link -- http://www.motorcyclecruiser.com/tec...ce_fork_seals/

For those with no manual at all, this is a good general guide for many fork seal replacement procedures.

Motorsports Forum. - Fork Seals. (MC)

There is, also, video guide for all that want to change oil, and oil seals
YouTube - How To: Replace Springs and Re-Seal your SP-5 Forks